Such apparatuses are already known for testing the alcohol content in the exhaled breath, and estimating the alcohol content of the blood.
Among these known apparatuses for testing the percentage of alcohol, an ethylometer or Alcotest.TM. currently available in the market is shown on FIG. 1 of the enclosed drawings and comprises:
a means for sensing the alcoholic vapors in the breath, comprising a porous reactant mass 1 which progressively changes color by chemical reaction with said alcoholic vapors according to the volume of gas flowing through said mass, PA1 a hollow tube 2 opened at its longitudinal ends, wherein said mass is housed so that the exhaled air entering the tube by one end passes through the mass and flows out by the other end, PA1 a means for metering the alcohol content in the breath, comprising a graduation 3 on the portion of the tube containing the reactant mass, said graduation being calibrated according to a predetermined volume of gas passing through the mass, and PA1 a means for limiting the gas volume passing through the tube, comprising a flexible inflatable bladder 4, intended to be connected to one end of the tube and the inflation of which is limited to the aforementioned predetermined calibrating volume, said bladder being provided with a valve at its nozzle. PA1 a hollow tube opened at its two longitudinal ends, wherein said mass is housed, PA1 a means for determining the substance content of the fluid, comprising for instance a graduated metering means on the longitudinal portion of the tube containing the reactant mass, said means being calibrated according to a predetermined fluid volume flowing through the mass, PA1 wherein it comprises a means for monitoring the fluid volume passing through the tube, comprising a heat sensitive indicator for indicating that the reactant mass has reached a critical heating temperature corresponding to a fluid volume flowing through the mass equal to the aforementioned predetermined calibrating volume did pass through the tube and hence that the user must stop blowing.
The operation of this Alcotest.TM. consists of blowing into the limiting bladder until it is completely full, then completely emptying the bladder through the tube after inserting the nozzle 5 of the bladder onto an end of the tube, and finally comparing the graduated mark of reference 3 with the length of reactant which changed color, to obtain an evaluation of the alcohol content of the blood. However, this type of ethylometer exhibits many drawbacks, in particular risks of leakage in the limiting bladder itself and at its connection to the tube, whereas the apparatuses have no tightness deficiency. There results a great overcost to obtain such as tightness.
This apparatus is also complicated in use since it requires three separate operations for the user. On the other hand, when the test is negative, the reactant mass does not change color but reacts with the water vapor contained in the exhalation, which makes the tube unusable, namely inoperable for a subsequent use. However, nothing on the tube let's know whether it is unused or has already been used during a negative test, since the tube and the inflatable bladder are in two separated parts.
The object of this invention is therefore to overcome the aforementioned drawbacks and to provide a novel light-weight portable apparatus for determining or metering a given substance content of a fluid, which is simple to manufacture and to use.